1. Technical Field
Various embodiments of the present disclosure relate to lithography techniques and, more particularly, to a reflective mask used in extreme ultraviolet (EUV) lithography and methods of fabricating the same.
2. Related Art
Lithographic processes utilizing EUV rays have been developed to transfer fine pattern images from a photomask onto a wafer. The EUV rays have a short wave length of about 13.5 nanometers. Thus, a resolution of the lithographic processes utilizing the EUV rays may be improved. Photomasks used in the EUV lithographic processes have been mainly developed to have a reflective mask structure. That is, reflective masks have been widely used in the EUV lithographic processes. Each of the reflective masks includes a light reflection layer and light absorption patterns formed on a surface of a mask substrate. The light absorption patterns of the reflective masks may cause a mask shadowing effect. The mask shadowing effect may lead to an undesired phenomenon such as a pattern critical dimension (CD) difference between a horizontal exposure scanning direction and a vertical exposure scanning direction or a pattern shift.